1. Field
The invention is in the field of cytocentrifugation devices as used in cytocentrifugation apparatus and is particularly concerned with improvements to the cytocentrifugation device disclosed in the aforesaid copending application Ser. No. 07/788,310 assigned to Wescor, Inc., Logan, Utah, now U.S. Pat. No. 5,252,228 on Oct. 12, 1993.
2. State of the Art
The apparatus and device of the aforementioned Stokes and Quirante patent application (the Wescor apparatus and device) are improvements on the apparatus and device of the Alan J. Gordon U.S. Pat. No. 4,391,710 of Jul. 5, 1983 that is assigned to Shandon Southern Products Limited, Runcorn, England. In the patented Shandon apparatus (the Shandon "Cytospin"), multiple cytocentrifugation devices for holding a cell-containing sample liquid and flowing it onto a microscope slide for the deposit on such slide of cells contained by the sample liquid are individually removably mounted in a rotary carrier (rotor) of the apparatus. The cell-containing sample liquid flows along a sample retention chamber of tubular formation under the influence of centrifugal force to an absorption pad confronting a face of a microscope slide held by a slide holder portion of the device. Such slide holder is provided with clamping means for holding together the flanged discharge end of the sample retention tube, the absorption pad, and the microscope slide during operation of the centrifuge. The cell-containing liquid is introduced into the sample retention tube through a funnel formation at the feed end of such tube and all parts of each device, including the slide holder and clamping means, are removable as a unit from the rotary carrier or rotor of the apparatus.
The improvements made to the Shandon "Cytospin" apparatus and device by the Wescor apparatus and device developed prior to the present invention were directed toward achieving retention of a greater number of cells on the deposition face of the slide than had been possible theretofore, and included the positive retention of the cell-containing sample liquid in a sample chamber that feeds into a flow conduit extending between such chamber and the slide holder. Such slide holder incorporates the clamping means and is non-removably secured to the rotary carrier or rotor of the apparatus for the purpose of greater security in use of the apparatus.
One aspect of the Wescor device constituting an improvement on the Shandon "Cytospin" device was the provision of at least two chambers in line along a liquid delivery conduit that corresponds to the Shandon sample retention tube, except for being fed during centrifugation with an absorption-pad-wetting liquid from the one chamber that is forwardly located and therefore closer in line to the delivery end of the sample delivery conduit than is the chamber containing the sample liquid so that the absorption-pad-wetting liquid positively reaches the absorption pad in advance of the cell-containing sample liquid. At least a third chamber for containing a cell-fixative solution is preferably provided, being in line rearwardly of the sample chamber so as to positively deliver fixative solution to the cell-receiving face of the slide after deposition of the cells thereon.
A second aspect of the Wescor device is the provision of an absorption pad that is formed with a relatively thin marginal area surrounding the usual hole through which the sample liquid reaches the deposit face of the slide and with a relatively thick surrounding area for absorption and retention of the sample liquid after cells have been deposited on the deposit face of the slide within the area of such usual hole through the absorption pad. This, of course, is useful whether or not there are multiple in-line chambers according to the first aspect of such Wescor improvements.
A further aspect of the Wescor improved device, that may be utilized whether or not the foregoing aspects are employed, is the novel construction of the clamping means relative to the holder for the microscope slide and for the absorption pad.